Major problems associated with the screening of body fluids for drugs of abuse include the relatively low speed of analysis and the often poor reliability of the data. Capillary gas chromatography is acknowledged to be superior in performance to thin-layer chromatography and the immunoassays, but it is generally too slow to be of value in the screening of large numbers of samples. We propose to develop a high- speed capillary gas chromatograph which would be suitable for the analysis of drugs of abuse in just a few seconds. The heart of the new instrument would be a microbore column with an internal diameter of 50 mu m or less. To take advantage of the ultimate performance of this column, a revolutionary inlet system and low-dead-volume detector will be developed. High-speed chromatography with a concentration-dependent detector has the added advantage of greatly improved detection limit, so very small samples of body fluids would be adequate for analysis. A prototype instrument will be constructed and evaluated for the determination of amphetamines, barbiturates, opioids, and other drugs of abuse in body fluids.